Page 154 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Object Oriented Analysis and Design

Notes Advantages

Easy and efficient to construct and use
More readily repairable

Disadvantages

No rollback
No direct complex structure support

Complex structure requires a grammar for file Format
Flat File Storage and Retrieval

Useful to define two components (or classes)
Reader reads file and instantiates internal object Structure
Writer traverses internal data structure and writes out Presentation
Both can (should) use formal grammar

Tools support: Yacc, Lex.
Java Data Marshalling

Provides a means of “serializing” a set of objects
Requires classes to implement the “Serializable” Interface.
Stream can be written/read to a file
Stream can be written/read to a network socket

Serialization Example:

Figure 12.4: Serialization Example

private void
writeObject(java.io.ObjectOutputStream out)
throws IOException;
private void
readObject(java.io.ObjectInputStream in)
throws IOException, ClassNotFoundException;

FileOutputStream ostream = new
FileOutputStream("t.tmp");
ObjectOutputStream p = new
ObjectOutputStream(ostream);
p.writeInt(12345);
p.writeObject("Today");
p.writeObject(new Date());
p.flush(); ostream.close();

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